The serotonin transporter (SERT) and other monoamine transporters operate in either a forward transport mode, where the transporter undergoes a full transport cycle, or an exchange mode, where the transporter seesaws through half-cycles. Amphetamines trigger the exchange-mode leading to substrate efflux. This efflux was proposed to rely on the N-terminus, which was suggested to adopt different conformations in the inward-, outward-facing and amphetamine-bound states. This prediction was verified by tryptic digestion of SERT-expressing membranes: in the absence of Na+, the N-terminus was rapidly digested. Amphetamine conferred protection against cleavage suggesting a relay between the conformational states of the hydrophobic core and the N-terminus. We searched for a candidate segment, which supported the conformational switch, by serial truncation removing 22 (ΔN22), 32 (ΔN32) or 42 (ΔN42) N-terminal residues. This did not affect surface expression, inhibitor binding and substrate influx. However, amphetamine-induced efflux by SERT-ΔN32 or SERT-ΔN42 (but not by SERT-ΔN22) was markedly diminished. We examined the individual steps in the transport cycle by recording transporter-associated currents: The recovery rate of capacitive peak - but not of steady-state - currents was significantly lower for SERT-ΔN32 than that of wild-type SERT and SERT-ΔN22. Thus, the exchange mode of SERT-ΔN32 was selectively impaired. Our observations show that the N-terminus affords the switch between transport modes. The findings are consistent with a model, where the N-terminus acts as a lever to support amphetamine-induced efflux by SERT.
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2jeoGDl
via IFTTT
Εγγραφή σε:
Σχόλια ανάρτησης (Atom)
Δημοφιλείς αναρτήσεις
-
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2jCvX3K via IFTTT
-
Treatment effectiveness holds considerable importance in the association between service quality and satisfaction in medical service studies...
-
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2pbGdiN via IFTTT
-
Vol.25 No.2 from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/1P7bHxT via IFTTT
-
Publication date: Available online 16 January 2017 Source: International Journal of Pediatric Otorhinolaryngology Author(s): Kaveh Karimn...
-
Daily Mail Sarah was diagnosed with the cancer that killed Steve Jobs Daily Mail The symptoms Sarah Smith experienced on and off for...
-
Omalizumab is a treatment for asthma that has a success rate of approximately 40% to 50%.1 Recent mechanistic studies have suggested that ba...
-
Understanding Head And Neck Cancers - The Southeast Sun ... The Southeast Sun (NAPSI)—According to the Centers for Disease Control an...
-
Abstract Background Henoch–Schönlein purpura is the most common vasculitis in children. Its long-term prognosis depends on renal involve...
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου